The villages of Buttevant and Bartlemy lie a few dozen kilometres apart in the heart of County Cork in the far south of Ireland. They’re tiny villages – populations 1,750-odd and 700-odd, respectively – and ordinarily have little to do with each other. However, they’re locked now in cordial competition over their right to a horse that died nearly two centuries ago – or that may never have existed at all.

When the National Army Museum in London reopens this spring, its exhibits will include the refurbished skeleton of Marengo, Napoleon’s celebrated white charger. This was, reportedly, the horse that won its name after bearing Napoleon to victory in northern Italy, and that then carried him through Austerlitz and Jena, back in slumped defeat from Russia, and finally at Waterloo. This is – also reportedly – the horse in Jacques-Louis David’s “Napoleon Crossing the Alps,” the brawny stallion with spinning eyes and a streaming mane, reared up at Great St. Bernard Pass. When I first saw the portrait it seemed too magnificent to be true, and it was: Napoleon had ridden a sure-footed alpine donkey through the mountains, but that was not a mount fit for an emperor. He wanted to be portrayed, he instructed David, “calme, sur un cheval fougueux” – “calm, atop a fiery horse.”

In its orthodox biography, Marengo was an Arab stallion captured by Napoleon’s forces in Egypt, after the Battle of Abukir in 1799. As the French routed the Ottomans, their opponents’ untended horses began to gallop all over the battlefield in panic. Hundreds of these horses were taken; one, having been shipped to France, became a favourite of Napoleon’s. “All the while he was waiting for his rider, he did not seem at all graceful,” Constant, Napoleon’s valet, wrote of this horse in his memoir. “But the moment he heard the drums beat to announce the Emperor’s coming, he drew himself up proudly, shook his mane, and pawed the ground with his foot, and so long as the Emperor was in the saddle he looked the most beautiful horse that anyone could hope to see.”

But the horse, which was purchased by a lieutenant colonel after Waterloo, doesn’t belong in London at all, the Irish maintain; it belongs in County Cork, where the French bought Marengo in one of Ireland’s great horse fairs. According to Bernard Moynihan, a local councillor, the skeleton ought to be in Buttevant, where the horse that became Marengo was sold many midsummers ago at the Cahirmee Horse Fair. He calls Cahirmee “the oldest horse fair in the world”; it continues to this day, held every July. “There’s a strong oral tradition in these parts, and the story of how the horse was sold to one of Napoleon’s officers – it’s well known,” he told me. Along with several other councillors, Moynihan has sent a letter to the National Army Museum, elaborating their claim. “We’ve recently had a round of archaeological excavations in Buttevant, and found a huge amount of historical artefacts. We’re hoping they can all go into a new museum, with Marengo as the centrepiece.”

John Arnold, a farmer and a historian of Bartlemy, will have none of that. Marengo was sold, he’s convinced, at the Bartlemy Horse Fair. “When you talk of evidence, it all begins to sound like a court case,” Arnold told me, with a laugh. “But I do have a couple of things that strongly suggest this. Buttevant don’t have a leg to stand on.” As far back as the 1830s, a village pub named Fitzgerald’s displayed a lithograph. “It was of a white horse, and the caption read: ‘Marengo, Napoleon’s famous horse, Bartlemy Fair, Middleton, County Cork,’” Arnold says. “That pub closed down, but the lithograph is still here in the village. Now, it’s possible that an entrepreneurial printer ran this lithograph off for many local fairs. But so far no other town has claimed to own a copy of it.”

Marengo’s Irish pedigree has been vaunted for more than a century. In the 1894-95 edition of a journal called the Scottish Antiquary, a letter-writer insists that Marengo was born Young Hidalgo – son of Hidalgo and grandson of Eclipse – and that he was bred in Wexford County by Annesley Brownrigg. “Mr Brownrigg’s granddaughters are now alive; they still possess hairs pulled from Marengo’s tail, which their grandfather used for his violin bow.” Foaled in 1797, the horse was sold three years later to a French officer for a hundred guineas. It was certainly a time when Europe’s armies bought thousands of horses in Ireland. When the Napoleonic Wars ended and the demand for horses slackened, the country slid into recession.

The contentions of Buttevant and Bartlemy might raise thorny questions of cultural patrimony – as if Marengo were a low-rent, equine version of the Elgin Marbles – were it not for the mystery surrounding the National Army Museum’s skeleton. In her excellent book, “Marengo: The Myth of Napoleon’s Horse”, Jill Hamilton finds that neither the Napoleonic archives nor the records of the imperial stables ever mention a horse called Marengo. In 1813, when Napoleon ordered portraits to be painted of his 23 horses, Marengo was not among them. It was only in London after Waterloo, when Napoleon’s legend began to be turned into an industry, that a horse of that name became well known. The lieutenant colonel, having failed to breed young Marengos from him, kept the horse until it died in 1831. Its skeleton went first to the Royal United Services Institute and then, in the 1960s, to the National Army Museum.

The most persuasive theory, Hamilton writes, is that Napoleon’s favoured horse – the horse nabbed in Egypt; the horse of the successful campaigns at Marengo, Austerlitz and Jena; perhaps the horse he rode at Waterloo – was a charger called Ali. “Marengo” may have just been a later billing, bestowed on the horse by London impresarios with an ear for a catchy name. But it’s impossible to be certain. Napoleon loved sleek, white stallions, and he loved to ride; over a 15-year reign, he used at least a hundred horses. Marengo will, in all probability, continue to reside at the National Army Museum; his prospects of relocation to Buttevant or Bartlemy are slim. Wherever he is, though, his display plaque should probably include the wise parenthetical that Paris’s Musée de l’Armée offers for its taxidermied specimen of another of Napoleon’s horses: “si c’est bien lui”, “if, indeed, this is him.”